1. Field of the Invention
The present invention relates generally to printing presses and, more particularly, to register cams for use with printing presses.
2. Description of the Related Art
The modern automatic platen press has not substantially changed since the introduction of this type of press in the early 1800""s. Basically, a platen press positions a substrate or print media, such as paper, on a platen and brings the substrate into contact with a die or form to print an image on the media. In operation, a number of additional steps are also involved. Initially, the dies or forms for printing are set in a form which is secured to a back-plate to properly position the characters or images for printing. Ink is applied to the raised surface of dies or forms. These raised surfaces define the characters or image to be printed. Finally, the print media is placed on the platen, precisely aligned and brought into contact with the form or die containing the characters or image by movement of the of the platen toward the back-plate. As the print media is pressed between the platen and the raised surfaces of the dies or forms, the image or characters is transferred to the print media. The particular mechanisms to carry out the printing process may vary from press to press but the main components of the modern platen press are generally similar or analogous. Although, in theory, the process is relatively simple, the particular components required to carry out this process are relatively complex.
Particularly with regard to the repeated positioning of the print media, the components of the platen press must act in precise harmony. A platen press typically uses a register assembly to precisely place the print media on the platen. The print media is received on the platen and transversely positioned to either left or right with a register gauge of the register assembly to precisely position the media for printing. Using the Kluge Automatic Platen Press manufactured by Brandtjen and Kluge of St. Croix Falls, Wis. as a specific example, the register gauge is one component of a cam-operated register mechanism that functions to precisely position the print media. The cam-operated register mechanism of the Kluge Automatic Platen Press includes a side register gauge as described-above to transversely push the printing media over the platen. The register gauge is mounted on a register rod. The register rod passes through an eye in a connecting rod that is attached at an opposite end to the register cam. To change between right and left registration, prior platen presses have required the removal of the registration cam and replacement with a separate registration cam having a reverse orientation of registration. The removal of a register cam requires the removal of a number of bolts and their subsequent replacement to secure the alternative register cam. This substitution procedure is both time consuming and imprecise, frequently requiring multiple adjustments to for the proper functioning of the press after replacement. Thus, the replacement of the register cam can require skilled labor adding to the costs for printing and decreasing profits. Further, the changing of registration creates the opportunity for loosing the nuts and bolts, or screws used to fasten the register cam to the registration assembly. If replacement parts are unavailable, valuable printing time above and beyond the normal extended time for replacing a register cam can be lost. Therefore, a need exists for a platen press that permits a simple and cost effective apparatus and method for changing the direction or degree of registration. Further, a need exists for a register cam that does not require the removal of the cam from the press to facilitate changing the direction or degree of registration.
The present invention meets the above needs and provides additional improvements and advantages that will be recognized by those skilled in the art upon review of the present disclosure. In a preferred form the present invention provides a simple, reliable apparatus and methods for changing the rate, degree or direction of registration in a printing press.
In one aspect of the present invention, a register cam including a body and at least two cam arms is provided. The cam arms secured to and extending outwardly from the body. The cam arms can be movably connected to the body to permit the cam arms to be locked in one of a first position and a second position relative to the body. In the first position, a first face of the register cam contacts an edge of a gripper bar and in the second position a second face contact an edge of the gripper bar. The body can include a longitudinal bore and a transverse cavity. The transverse cavity can being shaped to securedly and removably receive a detent that can extend from an axis which connects the at least two cam arms. The detent can be shaped to be received within the transverse cavity to lock the at least two cam arms in one of the first and second positions. A rod can also be secured to the axis and can extends from the axis. When a rod is included, the rod can extend into the longitudinal bore of the body to rotatably secure the at least two cam arms to the body. A set collar can also be secured to the rod to retain the shaft within the longitudinal bore. The body can include a slot to receive the set collar. The slot can be coextensive with at least a portion of the longitudinal bore so that the set collar can positioned within a slot. The rod can include a compressible element secured between a first end of the slot and the set collar. Thus, the compressible element can compressionally secure the detent within the transverse cavity of the body and prevent the rotation of the at least two cam arms relative to the body around a longitudinal axis of the rod. The compressible element can be a coil spring positioned about the rod between the first end of the slot and the set collar.
In another aspect of the present invention, a register cam having a body and at least one cam arm is provided. The at least one cam arm secured to and extending from the body. The at least one cam can be secured to the body to permit the arm to be rotated between at least a first position and a second position. The cam arm includes a first face and a second face. The first face having a first profile and the second cam having a second profile.
It is thus an object of the present invention to provide novel apparatus and methods for altering the registration of print media in a printing press.
It is further an object of the present invention to provide such novel apparatus and methods which can alter the registration of a printing press that is relatively simple and reliable.
It is further an object of the present invention to provide such novel apparatus and methods which can alter the registration of a printing press expediently eliminating the downtime associated with changing traditional register cams.
It is further an object of the present invention to provide such novel apparatus and methods which can alter the registration of a printing press by hand without the need for substantial additional tools.